This invention relates to hermetic compressor and suction accumulator assemblies for use in refrigeration systems, and in particular, to a strap for securely fastening a suction accumulator to a hermetic compressor.
Most compressors adapted for use in refrigeration systems are designed for the compression of gaseous refrigerant. Under some circumstances, however, it is not unusual for a certain amount of liquid to flow from the evaporator into the inlet of the compressor. This condition, which is often referred to as "slugging", may occur after the system is shut down. If an accumulator is not provided, large quantities of condensed refrigerant return through the suction line to the crankcase of the compressor. When the compressor is restarted, the large quantity of liquid refrigerant present therein results in abnormally high pressures which frequently cause blown gaskets, broken valves, etc. Suction accumulators, which are well known in the art, are provided in refrigeration systems to prevent this from occurring. Such accumulators prevent liquid refrigerant from entering the compressor cylinder, and act as storage reservoirs for the liquid refrigerant. The accumulators permit the liquid refrigerant to change to its gaseous state prior to entering the compressor suction tube and the compressor cylinder.
Many prior art arrangements have been provided for mounting accumulators in refrigeration systems. In the interest of providing a compact refrigeration system, it is preferred that suction accumulators be placed in close proximity to the compressor housing. A desirable feature of a refrigeration system is that very little pressure drop occurs in the suction tube leading from the accumulator to the compressor, so that suction tube losses will not detract appreciably from the efficiency of the system. In order to prevent appreciable pressure drop in the suction tube, it is desirable that the length of this tube is kept as short as possible. Additionally, it is desired that the accumulator and compressor be positioned in a manner such that the vibration of the accumulator is kept to a minimum.
One prior art arrangement for mounting accumulators in refrigeration systems is disclosed in U.S. Pat. No. 4,607,503, which is assigned to the assignee of the present application. This patent shows a mounting bracket disposed in the area between the accumulator casing and the compressor housing, which bracket secures the casing to the housing. While this bracket provides a reliable mount for the accumulator on the compressor, it does not prevent vibration of the accumulator body to the extent desired. This vibration may cause a weakening of the mount over a period of time, and in some cases may result in cracks being formed in the accumulator tube.
Another prior art arrangement utilizes a spring steel strap that holds the accumulator in close proximity to the compressor housing by spring tension. This strap is disposed circumferentially around the accumulator casing, and is somewhat bell-shaped in the area between the compressor and the accumulator. Although this spring steel strap imparts tension to hold the accumulator in close proximity to the compressor, the vibration of the accumulator may cause a lessening of this spring tension over a period of time, which ultimately results in even further vibrations and an increased noise level. As the spring tension of the strap continues to decrease, it becomes possible for the accumulator to dislodge from its position in close proximity to the compressor. This spring steel strap generally comprises a unitary piece of metal, and does not include any means for varying the spring tension.
Other straps for mounting an accumulator casing on a compressor housing have been used. One of these comprises a U-shaped bracket affixed to the housing of the compressor. This U-shaped bracket has two outwardly extending flanges, and the accumulator is placed adjacent to the compressor and within the U. A mated bracket is placed over the accumulator in relationship with the housing bracket. This bracket is attached to the U-shaped bracket by screws positioned on each side of the accumulator which engage the housing bracket at these flanges. Although the bracket holds the accumulator near the housing, it is necessary to screw the bracket on both sides of the accumulator. In addition, this arrangement does not impart any spring tension to the assembly. Thus, it is believed that the vibration of the accumulator may eventually loosen the screws and weaken this mount, resulting in an increased noise level and possibly a cracking of the accumulator tube.
It is therefore desired to provide a mount for a hermetic compressor and accumulator assembly wherein the accumulator is firmly held in close proximity to the compressor. Also, it is desired to provide such a mount wherein the vibration of the accumulator and the noise level of the system are kept within acceptable levels.